What are the treatments for respiratory acidosis, respiratory alkalosis, metabolic acidosis, and metabolic alkalosis in adults and pediatrics?

Treatment of Acid-Base Disorders in Adults and Pediatrics

RESPIRATORY ACIDOSIS

The primary treatment for respiratory acidosis is to restore adequate ventilation through mechanical support or treatment of the underlying cause, not alkali therapy. 1, 2

Treatment Algorithm

Acute Respiratory Acidosis:

• Establish mechanical ventilation immediately for patients with acute Type II respiratory failure from pulmonary edema, COPD exacerbation, asthma, or neuromuscular causes 2
• Use ketamine with atropine premedication for intubation in hemodynamically unstable patients, as it maintains cardiovascular stability through NMDA receptor blockade 1
• Avoid etomidate for intubation as even a single dose is independently associated with increased mortality in septic shock due to adrenal suppression 1
• Mild hyperventilation may compensate for concurrent metabolic acidosis, but excessive ventilation impairs cardiac output, particularly with hypovolemia 1

Chronic Respiratory Acidosis:

• Treat the underlying pathophysiology (COPD, neuromuscular disease, central nervous system disorders) 3, 2
• Renal compensation through bicarbonate retention typically normalizes pH over time 3
• Sodium bicarbonate is NOT indicated for pure respiratory acidosis as it produces additional CO2 that cannot be eliminated with inadequate ventilation 1, 4

Pediatric Considerations

• Intubation and ventilation should be considered early in children not rapidly stabilized with fluid resuscitation 1
• Sedation and ventilation facilitate temperature control and reduce oxygen consumption by up to 40% of cardiac output 1

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METABOLIC ACIDOSIS

For metabolic acidosis, treat the underlying cause first; sodium bicarbonate is reserved for severe acidosis (pH <7.20) after establishing effective ventilation, and only for specific indications. 1, 5

Treatment Algorithm by Etiology

Lactic Acidosis (Type A - Shock/Hypoperfusion):

• Restore tissue perfusion and oxygen delivery as the primary intervention 5
• Monitor lactate levels (>2 mmol/L indicates tissue hypoxia), base deficit, and pH serially to assess shock severity and treatment response 5
• Maintain hemoglobin ≥10 g/dL to optimize oxygen delivery 1
• Avoid hypothermia, hypocalcemia, and worsening acidosis during resuscitation as these exacerbate coagulopathy 5
• Sodium bicarbonate for type A lactic acidosis can be hazardous under conditions of hypoxemia, inadequate circulation, and limited ventilation 6

Sodium Bicarbonate Indications (Pediatric & Adult):

• Documented metabolic acidosis ONLY after effective ventilation is established 1
• Hyperkalemia 1
• Sodium channel blocker (tricyclic antidepressant) overdose: titrate to maintain serum pH 7.45-7.55, followed by infusion of 150 mEq NaHCO3/L solution 1
• Dosing (Pediatric): 1-2 mEq/kg IV/IO given slowly; use only 0.5 mEq/mL concentration for newborns 1
• Do NOT give by endotracheal route 1
• Do NOT mix with vasoactive amines or calcium 1

Alternative Buffer - THAM:

• Preferred over sodium bicarbonate when renal failure is present, or when hypoxemia, inadequate circulation, and limited alveolar ventilation coexist 6
• THAM does not increase PaCO2 and is renally excreted 6

Continuous Renal Replacement Therapy (CRRT):

• Indicated when renal failure complicates acidosis management 6
• Use bicarbonate-based solutions for CRRT buffer 7

Hyperchloremic Acidosis:

• Avoid overresuscitation with chloride-rich solutions in trauma or hemorrhagic shock 6
• Determine anion gap: normal anion gap indicates bicarbonate loss or chloride salt ingestion 4

Pediatric-Specific Dosing

• Calcium chloride 20 mg/kg (0.2 mL/kg of 10% solution) IV/IO for hypocalcemia complicating metabolic acidosis; give slowly and monitor heart rate 1
• Administer through central venous catheter when possible to avoid extravasation injury 1

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METABOLIC ALKALOSIS

Metabolic alkalosis treatment depends on urinary chloride levels: saline-responsive alkalosis (<10 mEq/L urinary Cl-) requires volume repletion with normal saline, while saline-resistant alkalosis requires potassium replacement. 4

Treatment Algorithm

Saline-Responsive Alkalosis (Urinary Cl- <10 mEq/L):

• Usually due to gastric H+ loss (vomiting, nasogastric suction) 4
• Administer normal saline solution to restore volume and chloride 4
• Correct concurrent hypochloremia (present in 82.2% of cases) and hypokalemia (33.3% of cases) 8

Saline-Resistant Alkalosis (Urinary Cl- moderately low):

• Not due to gastric losses; does not respond to saline alone 4
• Requires potassium replacement as primary therapy 4
• Consider discontinuing diuretics or corticosteroids for 24-48 hours 8

Acetazolamide for Refractory Cases:

• Indicated when metabolic alkalosis complicates chronic respiratory acidosis (hypercapnia) in patients on diuretics or steroids 8
• Dose: 500-750 mg daily for 48 hours after stabilization 8
• Produces significant decreases in pH and HCO3-, with improvement in PaCO2 and PaO2 8
• Discontinue if metabolic acidosis develops (occurs in 11.1% of patients) 8
• Corrects hypochloremia and hypokalemia effectively 8

Avoid:

• Do NOT use bicarbonate-containing fluids in volume-depleted patients with metabolic alkalosis 7
• Avoid inappropriate fluid therapy that worsens alkalosis 7

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RESPIRATORY ALKALOSIS

Treat the underlying cause of hyperventilation; for mechanically ventilated patients, adjust ventilator settings to normalize PaCO2. 7, 9

Treatment Algorithm

Acute Respiratory Alkalosis:

• Identify and treat anxiety or hyperventilation syndrome 7
• For mechanically ventilated patients: adjust ventilator settings to reduce minute ventilation 7
• Metabolic compensation occurs initially through cellular HCO3- uptake and intracellular buffering by phosphates and proteins 9

Chronic Respiratory Alkalosis:

• Renal compensation through decreased HCO3- reabsorption normalizes arterial pH over time 9
• Address underlying causes (CNS lesions, hypoxemia, pulmonary disease, liver failure) 9

Combined Respiratory and Metabolic Alkalosis:

• Presents with pH >7.45, decreased PaCO2, and elevated bicarbonate 7
• Treat respiratory component by addressing hyperventilation or adjusting mechanical ventilation 7
• Avoid bicarbonate-containing fluids 7
• Maintain appropriate fluid balance to avoid worsening respiratory status in acute lung injury 7
• Avoid overly rapid correction which may lead to new acid-base imbalances 7

Special Populations

• Liver failure patients: Use bicarbonate-based solutions for fluid therapy 7
• Acute lung injury: Maintain fluid balance carefully to prevent respiratory deterioration 7

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Critical Pitfalls to Avoid

• Never use sodium bicarbonate for pure respiratory acidosis - it generates CO2 that cannot be eliminated 1, 4
• Never use etomidate for intubation in septic shock - associated with increased mortality 1
• Never give sodium bicarbonate before establishing effective ventilation in cardiac arrest or metabolic acidosis 1
• Never use sodium bicarbonate by endotracheal route 1
• Never mix sodium bicarbonate with vasoactive amines or calcium 1
• Never use sorbitol-containing activated charcoal in children <1 year if treating concurrent ingestions 1
• Never correct acid-base disorders too rapidly in critically ill patients 7